1. Field of the Invention
The invention relates to stereophonic sound systems in general and more particularly to speaker enclosures for use therewith.
2. Description of the Prior Art
Several different approaches to the problem of enclosing a sound speaker presently exists in the prior art. Among these are the flat baffle, the open back enclosure, the infinite baffle, slotted enclosures which are designed to let out sound emanating from the back of the speaker, acoustic labrynths and enclosures built around the principles of horn design. An example of the latter is the Klipsch folded horn enclosure described in U.S. Pat. No. 2,310,243, the construction of which is familiar to all those skilled in the art of enclosure design. Various combinations of these devices will be found in the prior art as well.
An essential function of the speaker enclosure is to deal with the sound radiating from the rear of the speaker cone. A cone in motion alternately compresses and rarefies the air in front and in back of it. Since these two wave trains generated by the speaker are out of phase, care must be taken in the design of the enclosure to ensure against cancellation of one set of waves by the other. This design consideration is particularly important for middle and low frequency range sound reproduction.
Many speaker enclosures simply attempt to eliminate the effect of the sound radiation from the back of the speaker. This is illustrated by the construction known as the infinite baffle wherein a speaker is mounted in a wall between two rooms. The wall is of such large size and volume that it shields the speaker's front radiation from its rear radiation and the latter is completely lost. Other designs attempt to recover and make use of the radiation from the back of the speaker. One such approach is shown in U.S. Pat. No. 3,523,589.